Study and compare the levels of IgA antibody EBV-VCA in the native Caucasian French population, migrant Arab populations living in France, Tunisians, and Chinese in Hong Kong. Follow up all the NPC patients in these populations during surgery or therapy and thereafter study the levels of IgA antibody in order to evaluate its potential use in treatment and control of NPC. Include sera and saliva from patients for evaluation with tumors of head and neck region as well as from health subjects and healthy members of NPC families. Make available limited quantities of these sera on request through the project office to other investigators for EBV serological work or other related studies.